Slacker is a cheap/good value frame with plain gauge tubes and super slack head angle. If you go for a double+bash and run a bigger double ring (say 34 or 36t) then the chainstay clearance (with the intended 50mm spacing on the cranks) is fag paper tight. Not a massivey big deal but has lead to a few jammed chain problems. Price of being able to run big tyres I guess. Apparently you can "squeeze"/deform/crush the chainstay so clearance is better.

The tubes are regular old DN6 / 4130 cromoly equivalents (I think :-S

Personally went for 16" at 5'10" and found it good. Bit short for climbing / general riding but manageable. Really good with the saddle out the way or when doing tech stuff where you're moving around more on the bike.

Thought the BFe was (unkindly?) referred to as a Soul with more meat on it. Glancing at their site the HA is much steeper than a Slacker. 853 tubing as well by the looks of it. Oh, and 3 or 4 times the price.

On the steep tech cimbs at Stainburn when I first rode it there was a disconcerting flip-flop sensation. However, this became less noticeable and no issue after I'd ridden it a bit more. I guess you inherently adjust to it. Fitting it with forks that you can wind down for climbs would probably be a good idea.

It's cheap / good value and fun. I ran it with Pikes at 140, although I believe it's built to run anything between 100 to 150 I wonder if 110 might be a teeny bit short. Probably fine.

I've actually ridden both, as after seeing the numbers and Brant's raving I had to see what was what. The Summer Season is LOADS heavier than a BFe, and for a given fork travel about 3 deg slacker. That said, with 140mm forks the BFe ain't exactly slacker either, running at around 68 deg with rider on board. The key difference at that fork travel is that the BFe won't climb as well on steeper tech stuff, because the seat angle isn't as steep as the Summer Season, so some wind down forks will help a lot there. I found the SS very planted on technical climbs. Down the other size it just kind of bulldozed through things, kinda like a full sus, whereas you can chuck a BFe around and use your body weight to influence what's going on much, much more easily. The SS is super stable, to the point of almost excluding the rider from what's going on, even in pretty crazy rocks. The BFe is much more interactive, for want of a better synonym.